Just set the picture background to be left rather than center
Code:
background: url("images/intro_gasthem.png") no-repeat scroll left top transparent
That will remove the 1px bug. (which is caused by the container being 940px and the image only being 937px wide. Centering that obviously would leave a 1px border either side roughly)
And for the bottom border add the border-bottom to
Code:
.odd p {
border-bottom: 1px solid #000;
}